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and 1H and 13C NMR spectra of DHPDS, TPTA, and 3b are
described in the Supporting Information, respectively. Ther-
mally induced polymerization of 3a, molecular weight, and
Mw/Mn of 4a are also described in the Supporting
Information.
(CHAOH), 50.2 (ArACH2AN). 39.4 (SACH2ACH). ELEM. ANAL.:
Calcd for C23H23N2O3S: C, 70.20%; H, 5.89%; N, 3.56%, S,
8.15%. Found: C, 70.08%; H, 5.60%; N, 3.55%, S, 7.90%. The
1H and 13C NMR spectra were shown in Figure 1 and Sup-
porting Information Figure S-4.
Measurements
CONCLUSIONS
1
NMR spectra (400 MHz for H, dCHCl3 ¼7.26 ppm, dDMSO-d
¼
6
A new strategy for functionalization of 1,3-benzoxazine has
been developed based on preparation and usage of a novel
1,3-benzoxazine 1 bearing thiol moiety. The thiol moiety on
benzoxazine 1 was generated by reductive scission of disul-
fide linkage of a bifunctional benzoxazine 2 and was con-
veniently used for the addition reaction with GPE, to prove
the feasibility of our concept that 1 would be an useful
building block for synthesizing various benzoxazine-contain-
ing molecules based on the high nucleophilicity of thiol
that allows its highly efficient reactions with various elec-
trophiles. Another advantage of this strategy is the high po-
lymerization ability of benzoxazine 3a formed by the reac-
tion of 1 and epoxide, to which the sulfide group located
at the para position to the oxygen atom of the benzoxazine
would have been contributing to some extent. Further
investigation for applying the present strategy based on uti-
lization of the thiol-functionalized benzoxazine 1 to devel-
opment of various benzoxazine-containing materials is
ongoing.
2.40 ppm; 100.6 MHz for 13C, dCHCl3 ¼ 77.00 ppm) were
obtained on a Varian NMR spectrometer model Unity INOVA.
Chemical shift d and is given in ppm. Number average molec-
ular weight (Mn) and weight average molecular weight (Mw)
were estimated from size exclusion chromatography, per-
formed on a Tosoh chromatograph model HLC-8120GPC
equipped with Tosoh TSK gel-Super HM-H styrogel columns
(/6.0 mm ꢁ 15 cm), using THF as an eluent at the flow rate
of 0.6 mL/min after calibration with polystyrene standards.
Synthesis of 2
A mixture of DHPDS (7.50 g, 30 mmol), TPTA (6.3 g, 20
mmol), paraformaldehyde (1.8 g, 60 mmol), and toluene (60
mL) was heated with refluxing for 4 h. The reaction mixture
was ꢀ cooled to room temperature and left overnight at
0–5 C in a refrigerator (Scheme 1). The resulting precipitate
was collected with suction, washed with n-hexane, and
recrystallized from dichloromethane and n-hexane (volume
ratio ¼ 2:1) to obtained 1 (9.36 g, 19.4 mmol, 64%) as a
ꢀ
white crystal: Melting point ¼ 136–137 C.
This work was financially supported by The Yokohama Rubber
Co., Ltd.
1H NMR (in CDCl3) d 7.3–6.7 (16H, aromatic), 5.4 (4H, O-
CH2-N), 4.6 (4H, Ar-CH2-N); 13C NMR (in CDCl3) d 154.7–
117.7 (Aromatic), 154.7 (C-OACH2), 148.0 (C-N(CH2)CH2),
128.3 (C-S), 79.7 (O-CH2-N), 50.3 (Ar-CH2-N). ELEM. ANAL. of
1: C28H24N2O2S2: C, 69.39%; H, 4.99%; N, 5.78%, S, 13.23%.
Found: C, 69.10%; H, 4.89%; N, 5.74%, S, 12.98%. The spec-
tra are shown in Figure 1 and Supporting Information Figure
S-3.
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1:2): Melting point ¼ 100–101 C.
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1H NMR (in CDCl3) d 7.3–6.7 (13H, aromatic), 5.3 (2H,
OACH2AN), 4.6 (2H, Ar-CH2-N), 4.0 (3H, PhOACH2A
CHAOH), 3.1 (2H, S-CH2), 2.7 (1H, CH2AOH); 13C NMR (in
CDCl3) d 158.4–114.6 (Aromatic), 158.7 (CAOACH2ACH)
154.1 (CAOACH2), 148.1 (CAN(CH2)CH2), 125.5 (CASA
CH2ACH), 79.5 (OACH2AN), 70.0 (OACH2ACH), 68.6
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